Variable capacity pump



y 3 H. CENTERVALL 2,001,706

VARIABLE CAPACITY PUMP Filed April 28, 1932 2 Sheets-Sheet May 21, 1935.

H. CENTERVALL 2,001,706

VARIABLE CAPACITY PUMP Filed April- 28, 1952 2 Sheets-Sheet 2 24/ I 6246 2 -2 24-6 246 1 245 259 Q 254- 25/ i 746. 746 145 I 145 A)? I 50 l46t :1 (a, "a 14s 1 75/ I r a INVENTOR WW v M, M WW A; ATTORNEYS UNITEDHugo Centervall, Bro

STATES PATENT'OFFICE.

VARIABLE CAPACITY PUMP Manly Corporation,

poration of Delaware oklyn, N. Y., assignor to New York, N. Y., a cor-Application April 28, 1932, Serial No. 607,927

17 Claims.

This invention relatesto improvementsinpumps and fluid motors havingrotating radial cylinders and a non-rotatable central cylindrical valvemember.

One of the objects of the invention is to provide a pump or motor ofpie, compact and relatively inexpensive facture.

this class that is simto manu- Another and more specific object is toprovide a pump or motor of this class in which the pistons are at alltimes maintained substantially parallel with the boxes of theircorresponding cylinders.

The pump or motor selec ted for illustration is of the variable capacitytype such as used in hydraulic transmimions for obtaining variablespeeds and torques, but the structure may be used with like advantagesin pumps and motors of fixed capacity.

In the drawings Figure 1 is a central longitudinal'view, partly insection, of a pump or motor constructed according to the presentinvention and taken along the line of Fig. 2;

Fig. 2 is a cross sectional view of the device along the line 2-2 ofFig. 1;

Fig. 3 is a fragmentary transverse view, partly in section, the linksand cross 3-3 of Fig. 4;

showing an alternative embodiment of heads and taken along the line Fig.4 is a' corresponding longitudinal side view of the device shown in FigFig. 5 is a transverse vie a second alternative emb along the line ly insection, of

w, partly in section, of

odiment of the links, cross heads and associated mechanism,

5-5 of Fig. 6; and

Fig. 6 is a corresponding longitudinal view, partthe device as shown inFig. 5.

taken and taken along the line 5-6 of Fig. 5

Before explaining the present invention, it is to be understood that theinvention is not limited inits application to the details ofconstruction and arrangement of parts described herein and illustratedin the accompanying drawings, since the invention is capable of otherembodiments and of being practiced and carried out in various ways.

It is also to be understood that the phraseology or terminology usedherein is for the purpose of description and not for limitation,

and it is not intended to limit the invention beyond the terms of theseveral claims hereto appended as considered in view of the priorthereof.

Referring now to the casing is preferably forme art and the requirementsdrawings, the enclosing d in two portions and as here shown comprises arear member H to which is attached a front member l2, the two membersbeing held rigidly together by bolts l3. The enclosing casing forms thesupport for the device and the member II is accordingly provided withfeet i4.

The rear member II is formed with a hub l6 whose preferably tapered boreis adapted to receive the end of the stationary cylindrical valve member20 which is keyed against rotation as by a cap screw, not shown, in saidhub IS. The valve member 20 is held in place lengthwise of the hub I6 bynuts IS on the threaded outer ends of studs, indicated in dotted lines,which pass through suitable openings in the rear cover plate l0 andwhose inner ends are secured in the valve member 20.

The valve member 20 is provided with the usual valve ports 2| and 22which are separated by a transverse land 23. Longitudinal passages 20 25and 26 lead from the valve ports 2| and 22 respectively and extendthrough the rear end of the valve member 20. The rear cover plate I0 islikewise formed with two passages 21 and 28 adapted to register with thepassages 25 and 26, respectively, and to the outer ends of said passages21 and 28 are attached appropriate pipe connections 29 and 30,respectively.

The cylinder body 3| is rotatably mounted upon the valve member20 andfor this purpose is provided with a central bore 32, the fit of thepartsbeing such as to permit the cylinder body 3| to rotate freely whileforming a substantially fluid-tight running join To the cylinder body 3|is attached by pins 33 and cap screws 34 a flange 35 on one end of therevoluble shaft 36 which passes through a suitable opening in the frontcasing member l2, suitable packing 31 being used to prevent leakage. Thecylinder body 3| is provided with a plurality of radially disposedcylinders 38 having ports 39 on their inner ends adapted to registerwith the valve ports 2| and. 22, said ports 39 being preferably less inarea than the area of the cylinders 38.

Slidable within the cylinders 38 are pistons 40, here shown as formedintegrally with the cross heads 4|. Each cross head 4| is bored on eachof its ends to receive pins 42, held in place by any preferred means,not shown, by which said cross head is rockably attached to one end oflink members 45. The link members are here shown as having forked outerends provided with hubs 46 positioned on each side of the cross head 4|and which are adapted to receive the pins 42.

The inner ends of the link members 45 are likethat when the links 45 aone such wise forked and are formed with two hubs 41 and 46 of unequal'width and slightly offset with respect to the hubs 46. The arrangementis such on opposing ends of adjacent cross heads are turned at 180 toeach other, the forked inner end of one of said links 45 will fit withinthe other, as clearly shown in Fig. 1. This construction permits the useof identical links throughout while allowing the inner ends of saidlinks 45 on opposing ends of adjacent cross heads 4| to be journaledupon a common supporting pin 53 to be described later.

There is also provided a pair of oppositely positioned disks 50 formedwith oifset annular flanges 5| and with hollow hubs 52. The hubs 52surround the shaft 36 and the valve member 20 respectively and arereceived within the inner races 56 of a pair of bearing assemblies 51.The disks 56 are rigidly connected by the pins 53 which, as alreadyexplained, also carry the inner ends of two adjacent links 45 which arelocated between the opposing faces of the flanges 5|. Each pin 53 isformed near its outer ends with reduced portions 54 which pass throughsuitable holes in the flanges 5|. The ends of the pins 53 are threadedto receive the nuts 55 which hold the inner faces of the flanges 5|against the shoul ders formed by the reduced portions 54.

Each bearing assembly 51 is carried by a laterally movable slide whichis formed to receive the outer race 58. Each slide 60 is supported upona pair of parallel transverse slideways 6|, inner side of the casingmember I2 and another such pair being formed in the opposing inner sideof the casing member II. The slides 60 are fastened together in order toassure uniformity of their movement and position and for this purposeeach slide 60 is provided on both its ends with guide studs 62 whichproject through suitable openings in bosses 63 formed on the side wallsof the casing member II. The outer ends of the guide-studs 62 passthrough holes in the cross heads 64 and'are held in place with respectto said cross heads and with respect to each other by nuts 65 incooperation with shoulders 66 formed on said guidestuds 52. The innersurfaces of the bosses 63 form stops for'the reduced ends 61 of theslides 60, as shown in Fig. 2. Lateral movement of the slides by anypreferred means, such as an appropriate screw and nut device, not shown,connected to cross head 64 by means of the stud 68.

The position of the disks 50 relative to the center of rotation of thecylinder body 3| determines the length of the stroke of the pistons 40and the direction of flow of the fluid; hence, by movement of the slides60 the stroke of the pistons 46 may be infinitely varied at will fromzero (when the slides 60 are in their middle position and the centers ofthe disks 50 are coincident with the axis of rotation of the cylinderbody 3 I) to maximum (when the slides 60 are in their extreme outwardpositions). The direction of flow of the fluid may obviously be reversedby moving the slides 60 from one side to the other of their middle orzero stroke position.

When fixed stroke of the pistons is desired, it will be obvious that thebearing assemblies 51 may be carried upon any suitable non-movablesupports, such as annular recesses formed in the casing member I2 and inthe rear wall of the easing member II and adapted to receive the outerraces 56.

From the foregoing the operation of the device interchangeable.

pair of slideways being formed in the 60 may be effected will be clearto those skilled in the art. It will be evident that as the pistons 40reciprocate, the

links 45 are free to rock on both their inner and outer ends. As thelinks 45 are of equal length, each cross head 4-I will at all times bemaintained parallel to the centers of the corresponding pins 53, thusproducing a movement of each piston 46 parallel to its correspondingcylinder 38. There will be only a relatively small angular movement ofthe links 45 with respect to the pins 53 and the cross heads 4| (or thepins 42) and such angular movement is equivalent to a very smallrelative linear movement of the parts. It will further be evident thatthe motion of the disks 50 is constrained with respect to the movementof the cylinder body 3|.

The above described construction presents several advantages over pumpsand motors of this general type as previously constructed. Parallel linkconnections between the cross head of the pistons and the eccentricallysupported disks 50 insure a radial reciprocation of the pistons in thecylinders without imposing on the pistons any tendency to bind in thecylinders, thereby relieving the pistons of any lateral wear. Therocking motion of the links is small and consequently the rate ofangular motion about the bearings at the ends of the links frictionloss.

All of the parts are of simple design and are The pump is easy toassemble and when the bearings of the links have become worn the pumpmay be readily taken down and the worn parts replaced at small expense.As the cylinders are of tubular cross section throughout they may bereadily made of sections or steel tubing threaded or otherwise securedin the central hub, no external machining being required. By connectingthe pistons to the eccentric disk with the inwardly extending links thesize of the disks, the bearing assembly is considerably reduced, thebore of the disk being just sufliciently larger than the hub 01' thecylinder member to afford the desired eccentricity.

'Figs. 3 and 4 show an alternative embodiment of the links and crossheads. In this modification the links I45 are formed with a single hubI46 upon their outer ends and a single hub I 48 upon their inner ends,the hubs I46 and I 46 being substantially the same with andsubstantially in line witheach other. The cross head I 4| is likewisemodified to comprise two oppositely offset ends I42, each having a facesubstantially in line with the center of the cross head member I asclearly shown in Fig. 4. The pistons I40, here shown as secured to thecross heads I by a pressed fit, are positioned centrally with respect tothe center of the cross head I4 I. The hubs I46 on the outer ends ofthe-links I45 are rockably attached to the cross heads I by pins I43projecting from the faces of said cross heads that are substantially inline with their centers. As in is slow, thereby avoiding undue,

the first embodiment, the hubs I48 on the inner from opposing Figs. 5and 6 show a second alternative embod-.

iment of the link members and associated parts.

In this instance the outer ends of the links 245.

are forked and are formed with a pair of hubs 245 bored to receive thepins 242 by which they are rockably connected with the cross heads 24 l.The pistons 240 are here shown as formed integrally with the cross heads24!. The inner ends of the links 245 are formed with a pair of outwardlyextending segmental feet 241 which are received within circulartrackways 248 recessed within the opposing faces of the flanges 25l ofthe disks 250. Rollers 249 are inserted between the outer faces of thefeet 241 and the outer circumferential surfaces of the trackways 248,rollers 249 being limited by suitable stop pins 259 set in the flanges25!. The flanges 25! of the disks 250 are also provided with offsetprojecting arms 254 positioned so as not to interfere with the movementof the links 245 andbored to receive the pins 253 upon whose threadedends are nuts 255. The two disks 250 are thus rigidly connected. Thedisks 250 are also formed with hubs 252 which are received within theinner races 256 of the bearing assemblies 251, said bearing assembliesbeing movably supported as in the other embodiments.

In operation, as the pistons 24!! reciprocate, the hubs 246 on the outerends of the links 245 will rock on the pins 242 as in the otherembodiments and the segmental feet 241 will move within the trackways248 to permit the links 245 to rock with respect to the disks 250. Itwill be evident that whenever the pistons 240 and the cross heads 2 areunder load, the pressure will come on the outer faces of the feet 241(and as rollers 24!! are interposed between said outer faces of the feet241 and theoouter circumferential surfaces of the trackways248,'movement of the feet 241 will be translated into rolling motion;The inner faces of the feet 241 and the inner circumferential surfacesof the trackways 245 prevent inward radial movement of the links 245with respect to the disks 250 and hence the parts are at all times keptin proper relation to each other. Obviously rollers may also be placedbetween the inner faces of the feet 241 and the inner circumferentialsurfaces of the trackways 245 if desired, or all rollers may be omittedand plain bearings employed for either or both inner and outer faces ofsaid feet 241. It will also be evident that detachable hardened linersmay be employed on the trackways an.

By this construction the inner ends of the links are brought closer tothe center of rotation and anti-friction bearings may be substituted forthe plain bearings at the free ends of the links. The entire pumpconstruction is also more compact, the bearing centers being broughtcloser together and the two eccentric disks can be fastened directlytogether by the bolts extending between the cylinders, forming in effecta single rugged piece adapted to withstand heavy loads withoutdistortiom It is to be understood throughout that the usual fluid-tightpaokings are employed wherever required.

I claim: Y 1. In a structure of the class described, the combination ofa rotary cylinder structure having radial cylinders, pistonsin saidcylinders, a rotary member supported on bearings eccentric to thecylinder structure, and articulated connections between the pistons andsaid rotary memher, said connections comprising links extending inwardlyfrom the outer ends of the pistons to said member, said links havingtheir outer ends connected to their respective pistons at points themovement of said.

offset from the axes of the pistons circumferentially of the cylinderstructure and positioned exteriorly with respect to the bore of thecorresponding cylinde 2. In a structure of the class described, thecombination of a rotary cylinder structure having radial cylinders,pistons in said cylinders. a

rotary member supported on bearings eccentricto the cylinder structure,and articulated connections between the pistonsand said rotary member,said connections comprising parallel links on each side of each of saidpistons and between adjacent pistons, said links being pivotallyconnected to said pistons and said member,

3. In a structure-of the class described, the combination of a rotarycylinder structure having radial cylinders, pistons in said cylinders, arotary member supported on bearings eccentric to the cylinder structure,and articulated connections between the pistons and said rotary memher,said connections comprising a cross head at the end of each piston'andextending circumferentially of the cylinder structure, and links attheends of each cross head extending inwardly to said rotary member. I

4. In a structure of the class described, the combination of a rotarycylinder structure having radial cylinders, pistons in said cylinders,rotary mem rs supported eccentrically to said cylinder str re onopposite sides of said radial cylinders, connections between saidmembers extending axially between said cylinders, and articulatedconnections between said pistons and the connections between saidmembers.

5. In a structure of the class described, the combination of a rotarycylinder structure having radial cylinders, pistons in said cylinders,rotary members supported eccentrically to said cylinder structure onopposite sides of said radial cylinders, bolts connecting said rotarymembers and extending axially between said 'cylinders, and links mountedat one end on said bolts and at the other end attached to said pistons.

6. In a structure of the class described, the combination of a rotarycylinder structure having radially extending cylinders, pistons in saidcylinders, cross heads on the ends of said pistons, links at the ends ofsaid cross heads extending inwardly, a rotary member on each side ofsaid cylinders, eccentrically to said said rotary members beingsupported cylinder structure, bolts extending between said cylinders andconnecting said rotary members, said bolts constituting pivotal bearingsfor the inner ends of said links.

'7. In a structure of the class described, the combination of a rotarycylinder 'structurehaving radially extending cylinders, cylinders, crossheads on the ends of said pistons extending in the plane of rotation,links at the ends of said cross heads extending inwardly, a rotarymember on each side of said cylinders, said rotary members beingsupported eccentrically to said cylinder structure, said links havingbearing shoulders formed on the inner ends, flanges on said rotarymembers overlying said bearing shoulders and with bearing surfacespistons in said formed thereonfor co-action with the bearing shoulderson said links.

8. In a structure of the class described, the combination of a rotarycylinder structure having radical cylinders angularly disposed withrespect to each other, pistons in said cylinders, a rotary membersupported on bearings eccentric to the cylinder structur and articulatedconnections between each piston and said rotary memmember, said linkshaving their outer ends connected to the piston at points offset fromthe piston axis in the plane 01' rotation of said cylinderstructure andpositioned exteriorly with respect to the ,bore of the correspondingcylinder.

9. In a structure of the class described, the combination 01 a rotarycylinder structure having radial cylinders provided with inlet andoutlet ports on their ends nearest the center of rotation, pistons insaid cylinders, a rotary member supported on bearings eccentric to thecylinder structure, and articulated connections between each piston andsaid rotary member, said connections comprising links extending inwardlyfrom the outer end of the piston to said member, said links having theirouter ends connected to the piston at points oil'set from the pistonaxis in the plane of rotation of said cylinder structure.

10. In a structure of the class described, the combination of a rotarycylinder structure having radial cylinders, pistons in said cylinders,cross-heads on the outer ends of said pistons, a rotary member supportedon bearings eccentric to the cylinder structure, and articulatedconnections between each piston and said rotary member, said connectionscomprising links at the ends 01' each cross head'extendlng inwardly tosaid rotary member and positioned with respect to each other in a planesubstantially transverse the axis of rotation of said cylinderstructure.

11. In a, structure 01' the class described, the combination of a rotarycylinder structure having three or more radial cylinders, a piston ineach cylinder, a rotary member supported on bearings eccentric to theaxis of rotation ofsaid cylinder structure, and articulated connectionsbetween each of said pistons and said rotary member, said connectionscomprising for each piston member a parallelogram formation, movement ofsaid parallelogram formation relative to said rotary member beinglimited to movement of the members of said parallelogram formation withrespect to each other.

12. In a structure or the class described, the combination of a rotarycylinder structure having three or more radial cylinders, a piston ineach cylinder, a rotary member supported on bearings eccentric to theaxis of rotation of said cylinder structure, and articulated connectionsbetween each of said pistons and said rotary member, said connectionscomprising for each piston member a parallelogram formation positionedsubstantially transverse the axis of rotation, movement .of saidparallelogram formation relative to said/rotary member being limited tomovement of the members or said parallelogram formation with respect toeach other.

13. In a structure of the class described, the combination of a rotarycylinder structure having three or more radial cylinders, a piston ineach cylinder, a rotary member supported on bearings eccentric to theaxis of rotation of said cylinder structure, and articulated connectionsbetween each of said pistons and said rotary member, said connectionscomprising for each piston member a parallelogram formation one of whichmembers has a constant angular relationship with respect to the axis ofits corresponding cylinder, movement of said parallelogram formationrelative to said rotary member being limited to movement of the membersor said parallelogram formation with respect to each other.

14. In a structure or the class described, the combination or a rotarycylinder structure having three or more radial cylinders, a piston ineach cylinder, a rotary member supported on bearings eccentric to theaxis of rotation of said cylinder structure, and articulated connectionsbetween each of said pistons and said rotary members, said connectionscomprising for each piston mem her a parallelogram formation one ofwhich memhers is continuously maintained at substantially right anglesto the axis of its corresponding cylinder, movement of saidparallelogram formation relative to said rotary member being limited tomovement 01' the members of said parallelogram formation with respect toeachother.

15. In a structure of the class described, the combination of a rotarycylinder structure having radial cylinders, a piston in each cylinder, arotary member supported on bearings eccentric to the axis of rotation ofsaid cylinder structure, a cross-head on each piston extending with itsgreatest dimensions in a plane substantially transverse the axis ofrotation 01' said cylinder structure and having its ends positioned in aline substantially at right angles to said piston, and articulatedconnections between said cross head and said rotary member comprisingparallel links connected with each end of said cross-head and with saidrotary member at points equidistant from said cross head.

16. In a structure of the class described the combination of a rotarycylinder structure having radial cylinders, a piston in each cylinder, arotary member supported on bearings eccentric to the axis of rotation ofsaid cylinder structure, and articulated connections between each ofsaidpistons and said rotary member, said connections comprising for eachpiston a pair of links extending inwardly from the outer end of saidpiston to said rotary member said links being arranged in parallelogramformation in the plane of rotation so as to maintain said pistonparallel with the bore of its coacting cylinder.

17. In a structure of the class described the combination of a rotarycylinder structure having radial cylinders, a piston in each cylinder, arotary member supported on bearings eccentric to the axis of rotation ofsaid cylinder structure. and articulated connections between each oIsaid pistons and said rotarymember, said connections comprising for eachpiston and its coacting cylinder a pair of links oi equal lengthextending inwardly from the outer end of said piston to said rotarymember, said links being arranged in parallel relation one on each side01 said cylinder and in the common plane passing through the radialcenter lines of said cylindersthereby maintaining said piston parallelwith the bore of its coacting cylinder.

CEN'I'ERVALL.

